What You Can See on March 17

From Audubon’s Earth Almanac by Ted Williams and compiled in “Wild Moments,” edited by Connie Isbell, Illustrations by John Burgoyne, Storey Publishing, 174 pages. Dancing Gig The first whirligigs of spring, splattered like purple ink over a windless pond, swamp, or lazy meadow stream, will make the surface quiver at your stealthiest approach. If you wade or paddle, they will sense your presence by reading the ripples with their antennae. If you come by land, they’ll see you with the top parts of compound eyes, which allow them to simultaneously take in scenes above and below the surface. The only beetles that swim on the surface, whirligigs propel themselves with oarlike hind legs; when they dive they carry their own scuba tank in the form of an air bubble. They can also fly. Of the 60 species distributed throughout the United States and Canada most belong to two genera -- Dineutus (about half an inch long) and Gyrinus (a quarter-inch or less). The whirligigs you see now have spent the winter sleeping in the mud. Soon they will breed, lay eggs on the stems of submerged vegetation, and die. The new generation of adults will appear in late summer, forming aggregations of that can number in the thousands. Catching whirligigs is just difficult enough to make it grand sport for small children. Fish have an easier time of it, but once inside their jaws, whirligigs emit a vile-tasting goo that induces regurgitation. Uncommon Courtship Common terns are now courting, especially on islands, where gently sloping land embraces the sea and big lakes in northern temperate zones around the globe. Watch for their distinctive flight displays in which a male, shadowed by a female, flies along with a small fish in his bill. When she overtakes him, he’ll drop his head, turn away, and hold his wings high over his back. At the same time she’ll thrust her head forward and hold her wings down, then start a sharp downward glide, tilting from side to side. On the ground a male may march in front of the female in a semicircle, lower his head, raise his head, bend forward and kick back with his feet. Often he’ll carry a small fish, presumably a signal of his intention to copulate. The female expresses interest -- at least in the fish -- by emitting a ki-ki call and hunching over. Sometimes another male will ape this behavior, thereby acquiring a free meal. Also called sea swallows, these graceful, agile birds cover astonishing distances in migration. One individual, banded in Finland, was captured 16,000 miles away in Australia.